Unpredictable Weather Requires Proper Corn Management

Source: Purdue Extension | Feb 02, 2012

There may be no such thing as the "normal" growing conditions of old that many corn farmers have been longing for after enduring extreme weather in recent years, says Bob Nielsen, a Purdue Extension agronomist. Instead, he suggests corn growers look at a variety of management techniques to give crops the best chance at success – regardless of the weather.

"Many of us have a nostalgic memory of growing seasons where the crops emerged quickly, grew vigorously and uniformly, pollinated successfully, filled out grain completely and stood strong until harvested in the warm, sunny days of early fall," Nielsen says.

"I would suggest that maybe we have all been delusional with our nostalgia and that perhaps a more accurate definition of a 'normal' growing season is one that involves an unpredictable number of unpredictable extreme weather events, each occurring unpredictably with unpredictable severity."

The first way farmers can deal with uncertainty is to identify what influences yield – both positive and negative – and manage it accordingly.

Often, weather stress is compounded by other yield-influencing factors, so identifying and managing them can help growers "stress-proof" their cropping systems, Nielsen says.

"The process of identifying the yield-influencing factors that are important to specific fields is not easy," he says. "They may occur every year in a given field, or they may not. They often interact with other factors to influence yield. They often interact with soil type and texture and drainage conditions. And yield-influencing factors almost always interact with weather conditions."

Because there are so many possible yield-influencing-factor combinations, Nielsen says corn growers should strive to keep notes on what happens to a crop during an entire growing season. They also can draw upon their own experiences from a particular field.

He also suggests taking advantage of available resources, such as crop input retailers, crop consultants and Extension professionals.

"The bottom line is get out into your fields during the growing season, identify problem areas early while evidence is still there to aid diagnostics and figure out what's going on with your crops," Nielsen says.

Key considerations for farmers

Some key considerations for farmers include:

Field drainage. Poorly drained soils can hinder the establishment of vigorous corn stands by challenging the uniformity of roots and plant development. Improving tile or surface drainage reduces the risks of ponding or soggy soils, denitrification and soil compaction.

Soil erosion control and soil moisture conservation. In areas of rolling hills with high risks of soil erosion and reduced ability to retain soil moisture, Nielsen says it is important to minimize water runoff and maximize soil moisture retention. Some techniques include no-till or reduced tillage, strip-cropping, contour farming, terraces and other water control structures and fall and winter cover crops.

Hybrid selection. "The key challenge is to identify hybrids that not only have good yield potential but that also tolerate a wide range of growing conditions," Nielsen says. "The best way to accomplish this is to evaluate hybrid performance across a lot of locations. University trials are good for this exercise."

Nitrogen management. Because the eastern Corn Belt has poorly drained soils, ample rainfall and the risk of nitrogen (N) loss by either denitrification or leaching, growers need to pay special attention to N management. According to Nielsen, best management practices include avoiding fall applications, avoiding surface application of urea-based fertilizers without incorporation and adopting sidedress N application programs where practical.

Disease Management. Warm, humid summer weather conditions in the eastern Corn Belt are ideal for the development of many corn diseases, such as gray leaf spot and Northern corn leaf blight. The best ways to manage these diseases are by selecting hybrids for strong disease resistance characteristics, avoiding continuous-corn cropping systems, avoiding no-till cropping systems and responsibly using foliar fungicides.

"We're talking about a lot of common-sense agronomic principles that work together to minimize the usual crop stresses that occur every year and allow the crop to better tolerate uncontrollable weather stresses," he says.